Tubing head spool actuation through landing string

ABSTRACT

A landing string for landing a tubing hanger in a tubing spool has flow lines for actuating annulus access valves. A tubing string depends from the tubing hanger, and projects into a wellbore lined with casing when the tubing hanger is landed. Piping outside of the tubing spool connects to a bore formed through the tubing spool to provide access to an annulus between the tubing string and casing. The annulus access valve is in the flow line to control flow to the annulus. The valve is driven by an actuator that is operated by fluid in a flow line ported through the landing string, and in communication with the tubing spool when the tubing hanger is landed.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present disclosure relates in general to a subsea wellhead assembly, and in particular to controlling an annulus access valve via a landing string.

2. Description of Prior Art

A wellhead assembly is typically mounted over a hydrocarbon producing well for handling fluids produced from the well. Wells are generally lined with casing, where produced fluid flows from the formation adjacent the well, through perforations in the casing, and into the well. The produced fluids flow from the well to the wellhead through a tubing string that is supported by a tubing hanger in the wellhead assembly. The tubing hanger lands in a wellhead member, which is usually one of a wellhead housing, a tubing spool mounted on top of a wellhead housing, or a production tree. Various workover and completion operations require fluid circulation down the tubing and back up a tubing annulus surrounding the tubing, or vice-versa. Wellhead assemblies typically include flow passages, fittings, and valves that allow for selective access to the tubing annulus and provide a return path for circulation of the fluid pumped into the well.

One type of flow passage in a wellhead assembly is a tubing annulus passage extending through the body of the tubing hanger which communicates with the tubing annulus. In an offshore well completion, the operator may install a plug in the tubing annulus passage before the production tree is installed. After the tree is installed, the operator retrieves the plug with a wireline retrieval tool. Sometimes a tubing annulus valve is installed in a line that communicates with the tubing annulus passage for controlling flow to and from the annulus. In some subsea installations, the line is ported around the tubing hanger through the body of a tubing head spool or horizontal tree. In this case, the annulus valves are controlled by ROV, WOCS or from the tree mounted control system when the production controls umbilical is in place.

SUMMARY OF THE INVENTION

Disclosed herein are example methods and devices for remotely providing access to an annulus within a subsea wellbore. In one example, a subsea assembly includes an annular outer wellhead member, an annular inner wellhead member insertable within the outer wellhead member, a tubular string depending from the inner wellhead member, an annulus circumscribing the tubular string, a flow line having an end intersecting the annulus, and a valve in the flow line selectively moveable between an open position to a closed position. In this example, an actuator is coupled to the valve and is in communication with a motive source through a passage formed through the outer tubular and the inner tubular. The outer wellhead member can be a tubing head spool, the inner wellhead member can be a tubing hanger laudable in the tubing head spool, and the tubular string can be production tubing. In an example, the motive source can be one of a supply of hydraulic fluid or an electrical power source. The subsea assembly can further include an outer seal assembly in a portion of the passage in the outer wellhead member and an inner seal assembly in a portion of the passage in the inner wellhead member that communicate with one another when the inner wellhead member lands in the outer wellhead member. Alternatively, the valve is actuatable by a remotely operated vehicle. The inner wellhead member can be selectively connected to be part of a landing string, and wherein the passage extends through the landing string. In this example, the inner wellhead member is a tubing hanger, and the landing string is made up of a tubing hanger, a running tool, and a subsea test tree.

Also disclosed herein is a subsea assembly that includes a tubing head spool mounted over a wellbore and a landing string. The landing string includes a subsea test tree, a running tool connected to the subsea test tree, and a tubing hanger connected to the running tool and selectively insertable in the tubing head spool. Also included is an annulus access line having a portion projecting through the tubing spool, a valve in-line with the annulus access line and that is moveable between an open position and a closed position, and an actuator coupled to the valve and connected to a power source by a line extending through the landing string and tubing head spool. In an alternate embodiment, the landing string lands in the tubing head spool, and an annulus is formed around a lower portion of the tubing hanger that is accessible through the annulus access line. Portions of the line in the tubing head spool and tubing hanger can be passages formed in the tubing head spool and tubing hanger. In this example, further included is a seal assembly in the passage in the tubing hanger that selectively changes from a closed to an open configuration when the tubing hanger is landed in the tubing head spool. The subsea assembly can further include a plurality of passages in the tubing hanger that register with and are in communication with passages formed in the running tool. In this example, at least one of the passages contain an electrical line and wherein a fluid flows through at least another one of the passages.

Also disclosed is a method of handling a subsea assembly, where the subsea assembly includes a landing string having a tubing hanger. The method includes lowering the landing string subsea and landing the tubing hanger within a tubing spool, and selectively opening an annulus access valve to provide communication to an annulus circumscribing the tubing by communicating a motive source along a path that extends through the landing string. The motive source can be hydraulic fluid communicated to an actuator that is connected to the annulus access valve. Optionally, the motive source can be electricity communicated to an actuator that is connected to the annulus access valve. The method may further include closing the annulus access valve.

BRIEF DESCRIPTION OF DRAWINGS

Some of the features and benefits of the present invention having been stated, others will become apparent as the description proceeds when taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a side sectional view of an example of landing a tubing hanger with a running tool in accordance with the present invention.

FIG. 2 is an enlarged view of a portion of an example of the tubing hanger and running tool of FIG. 1.

While the invention will be described in connection with the preferred embodiments, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications, and equivalents, as may be included within the spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF INVENTION

The method and system of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings in which embodiments are shown. The method and system of the present disclosure may be in many different forms and should not be construed as limited to the illustrated embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey its scope to those skilled in the art. Like numbers refer to like elements throughout.

It is to be further understood that the scope of the present disclosure is not limited to the exact details of construction, operation, exact materials, or embodiments shown and described, as modifications and equivalents will be apparent to one skilled in the art. In the drawings and specification, there have been disclosed illustrative embodiments and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation.

An example of a wellhead assembly 10 being assembled is shown in a side sectional view in FIG. 1. The wellhead assembly 10 is being formed on a seafloor 112 and set over a wellbore 14 shown intersecting a formation 16 beneath seafloor 12. An annular wellhead housing 18 makes up a lower most portion of the wellhead assembly 10, and is shown anchored into the seafloor 12. An annular casing spool 20 coaxially mounts on an upper end of the wellhead housing 18, in which a casing hanger 22 is supported. Casing hanger 22 is a generally annular member, and has an oblique profile on its outer radius that lands in complimentary profiles within an inner surface of casing spool 20. A casing string 24 attaches on a lower end of casing hanger 22 and depends downward into wellbore 14. An annular tubing head spool 26 is illustrated mounted on an upper end of casing spool 20; and similar to casing spool 20, tubing head spool 26 has an inner radius with profiles on which a complimentary shaped tubing hanger 28 is being landed. A tubing string 30 couples to a lower end of tubing hanger 28 and coaxially inserts within casing hanger 22 below. Tubing string 30 projects further downward to within casing string 24. In the example of FIG. 1, tubing hanger 28 is part of a landing string 31 that includes a running tool 32 for attachment into the tubing hanger 28, and a subsea test tree 33 coupled to an upper end of running tool 32.

A portion of the wellhead assembly 10 is illustrated in FIG. 2 in an enlarged and side sectional view, where connection between running tool 32 and tubing hanger 28 is seen. In the example of FIG. 2, a series of passages 34, 36, 38, 40, 42, 44, 46, 48, 50 extend axially through the running tool 32. Shown formed axially from an upper end of tubing hanger 28 and within the body of tubing hanger 28 are passages 54, 56, 58, 60, 62, 64, 66, 70. The series of passages 34, 36, 38, 40, 42, 44, 46, 48, 50 respectively register with passages 54, 56, 58, 60, 62, 64, 66, 70 via connectors 72, 74, 76, 78, 80, 82, 84, 86, 88. Thus, by connecting the running tool 32 with tubing hanger 28, immediate communication and registration occurs between the respective passages in running tool 32 and tubing hanger 28.

Further illustrated in FIG. 2 are a pair of annulus access valves 90, 92 mounted in a portion of a line 94 shown outside of tubing head spool 26. Line 94 communicates with an annulus 96 formed in a space between tubing hanger 28 and casing spool 20. Line 94 may extend through a passage 97 formed in the side wall of tubing head spool 26, or may be piped up to the passage 97. Fittings 98, 100 are provided respectively on valves 90, 92, so that valves 90, 92 may be operated subsea by a remotely operated vehicle (ROV) 102. As is known, opening and closing of valves 90, 92 selectively provides access to annulus 96 for various workover and/or completion efforts that take place during the course of completing and/or operating a well.

In the example of FIG. 2, an actuator 104 is provided with valve 92 for selective opening and closing of valve 92. A motive source, such as hydraulic fluid or electricity, is provided to actuator 104 via line 106 shown projecting through the side wall of the tubing head spool 26 and into communication with passage 70. A connector 108 provides communication between line 106 and passage 70, which in one example may include a spheriseal assembly. An example of a spheriseal considered for use herein is described in Miller, U.S. Patent Application Publication No. U.S. 2013/0056219, which is assigned to the assignee of the present application, and incorporated for reference in its entirety for all purposes herein. Optionally, a line, wire, or tubing may be included in passage 70 for conveying the motive source through the tubing hanger 28 into line 106.

Further in the example of FIG. 2, line 106 connects with or projects through passage 110, shown formed in the sidewall of the tubing head spool 26. Passage 110 terminates adjacent tubing hanger 28 where it registers with connector 108. Optionally, the portion of passage 110 adjacent tubing hanger 28 can be a gallery 111 which circumscribes the inner surface of tubing head spool 26. As discussed above, passage 70 communicates with passage 50 shown in running tool 32. A power source 112 is schematically illustrated, which can be a hydraulic pump, a reservoir of hydraulic fluid, as well as an electrical power source. Line 114 attached to power source 112 conveys motive source from power source 112 to a designated destination. Power source 112 can be located above the sea surface and communicate with the wellhead assembly 10 (FIG. 1) through landing string 31 (FIG. 1). In an example, line 114 is in communication with passage 50 through a circuit (not shown) between power source 112 and landing string 31. As indicated above, passage 50 is in communication with passage 70 via connector 88, and passage 70 is in communication with line 106 through connector 108. Accordingly, power source 112 is in communication with actuator 104, and selective delivery of a motive source from power source 112 to actuator 104 can open or close annular access valve 92. In this manner, annulus access valve 92 can be controlled from a control room or other area where landing operations are being managed by allowing for actuation of the annular access valve 92 from above the sea surface. An advantage of automating operation of the annular access valve 92 is that ROV 102 is no longer necessary for providing access to annulus 96.

In one example of operation, landing string 31 is formed, and tubing hanger 28 and tubing 30 is suspended from running tool 32. As noted above, connecting tubing hanger 28 with running tool 32 registers series of passages 34, 36, 38, 40, 42, 44, 46, 48, 50 with passages 54, 56, 58, 60, 62, 64, 66, 70. Power source 112 is in communication with passage 50 in running tool 32 through line 114 and connections (not shown) between line 114 and passage 50. Landing the tubing hanger 28 within tubing head spool 26 puts passage 70 in communication with passage 110, thereby completing a circuit through which power source 112 communicates with actuator 104. Power source 112 can optionally be controlled by a controller 116, which can be an information handling device with memory for storing commands for automated operation. Controller 116 can also represent a means by which an operator can send commands to power source 112, where in an example the operator is in a rig, ship, or other vessel disposed on sea surface above the tubing head spool 26. A communication means 118 provides a link for communicating between controller 116 and power source 112, which can include hard wiring, electromagnetic waves, or acoustic signals. As such, an operator can control operation of annulus access valve 92 while in a vessel located on sea surface.

Embodiments exist wherein an actuator (not shown) is provided for annulus access valves 90. In addition to selective opening and closing of valve 92 via the landing string 31, emergency shutdown procedures may be formed in this manner through the landing string 31. Similarly, valves on horizontal trees may be controlled through the landing string control system. An advantage of annular access valve control through the landing string control system allows all functions necessary for an intervention to be controlled from a single system. This single path of control signals allows automatic sequenced closer of valves associated with the wellhead assembly 10 during an emergency shutdown and for the system to be moved into a failsafe configuration in the event of unintended disconnect or loss of control.

The present invention described herein, therefore, is well adapted to carry out the objects and attain the ends and advantages mentioned, as well as others inherent therein. While a presently preferred embodiment of the invention has been given for purposes of disclosure, numerous changes exist in the details of procedures for accomplishing the desired results. These and other similar modifications will readily suggest themselves to those skilled in the art, and are intended to be encompassed within the spirit of the present invention disclosed herein and the scope of the appended claims. 

What is claimed is:
 1. A subsea assembly comprising: an annular outer wellhead member; an annular inner wellhead member insertable within the outer wellhead member; a tubular string depending from the inner wellhead member and that is circumscribed by an annulus; a flow line having an end intersecting the annulus; a valve in the flow line selectively moveable between an open position to a dosed position; and an actuator coupled to the valve and in communication with a motive source through a passage formed through the outer tubular and the inner tubular.
 2. The subsea assembly of claim 1, wherein the outer wellhead member comprises a tubing head spool, the inner wellhead member comprises a tubing hanger landable in the tubing head spool, and the tubular string comprises production tubing.
 3. The subsea assembly of claim 1, wherein the motive source comprises one of a supply of hydraulic fluid and an electrical power source.
 4. The subsea assembly of claim 1, further comprising an outer seal assembly in a portion of the passage in the outer wellhead member and an inner seal assembly in a portion of the passage in the inner wellhead member that communicate with one another when the inner wellhead member lands in the outer wellhead member.
 5. The subsea assembly of claim 1, wherein the valve is actuatable by a remotely operated vehicle.
 6. The subsea assembly of claim 1, wherein the inner wellhead member is selectively connected to be part of a landing siring, and wherein the passage extends through the landing string.
 7. The subsea assembly of claim 6, wherein the inner wellhead member comprises a tubing hanger, and the landing string comprises the tubing hanger, a running tool, and a subsea test tree.
 8. A subsea assembly comprising: a tubing head spool mounted over a wellbore; a landing string comprising, a subsea test tree, a running tool connected to the subsea test tree, and a tubing hanger connected to the running tool and selectively insertable in the tubing head spool; an annulus access line having a portion projecting through the tubing spool; a valve in-line with the annulus access line and that is moveable between an open position and a closed position; and an actuator coupled to the valve and connected to a power source by a line extending through the landing string and tubing head spool.
 9. The subsea assembly of claim 8, wherein when the landing string lands in the tubing head spool, an annulus is formed around a lower portion of the tubing hanger, and that is accessible through the annulus access line.
 10. The subsea assembly of claim 8, wherein portions of the line in the tubing head spool and tubing hanger comprise passages formed in the tubing head spool and tubing hanger.
 11. The subsea assembly of claim 10, further comprising a seal assembly in the passage in the tubing hanger that selectively changes from a closed to an open configuration when the tubing hanger is landed in the tubing head spool.
 12. The subsea assembly of claim 8, further comprising a plurality of passages in the tubing hanger that register with and are in communication with passages formed in the running tool.
 13. The subsea assembly of claim 12, wherein at least one of the passages contain an electrical line and wherein a fluid flows through at least another one of the passages.
 14. A method of handling a subsea assembly that comprises a landing string having a tubing hanger, the method comprising: a. lowering the landing string subsea and landing the tubing hanger within a tubing head spool; b. selectively opening an annulus access valve to provide communication to an annulus circumscribing the tubing head spool by communicating a motive source along a path that extends through the landing string.
 15. The method of claim 14, wherein the motive source comprises hydraulic fluid and is communicated to an actuator that is connected to the annulus access valve.
 16. The method of claim 14, wherein the motive source comprises electricity and is communicated to an actuator that is connected to the annulus access valve.
 17. The method of claim 14, further comprising closing the annulus access valve. 